Support for `source` config option.

- Add support for `source` option to include config files.

- Example:- 
 ```bash
❯ tree
 .
├── 󱁻 hypr.conf
├──  hypridle.conf
├──  hyprland.conf
├──  hyprlock.conf
├──  hyprpaper.conf
```
the hypr.conf holds many vairables like path for wallpaper. i wanna import the variable to hyprpaper.conf. 
